Occasionally intermittent network anomalies can cause NUL characters (ASCII character /u0000) to be inserted into the file. Because these are valid characters in a JSON string (JSON Schema Validation: A Vocabulary for Structural Validation of JSON), files with NUL characters are not rejected due to schema validation and are passed to the Interrogation Data Loader process (IDL) for loading into PTAGIS. IDL then strips the NUL characters out of the transceiver messages and loads them into the database without the NUL characters included.

 

Because NUL characters are valid JSON string characters, they are counted and can cause a file rejecting during schema validation due to maximum field length: the FieldData element in the JSON file has a maximum length of 500 characters.

 

If an M5 file contains NUL characters, the following processing rules will be applied:

1.If the NUL characters cause a maximum field length (or any other type) validation failure during the JSON schema check, the file will be rejected. M5 File Manager can be used to remove the NUL characters and resubmit the file.

2.If the NUL characters do not cause any other JSON schema validation errors, the file will be processed by IDL and the NUL characters will be removed from the data that is loaded into the database, but will remain in the file.

Version: 1.08

Published: 11/12/2024